Emerging from her shaded hideout one recent morning, Satka spots her prey swinging just above the ground. The Amur leopard, native to far east Asia, leaps nearly straight up and takes a hefty bite.

But the prey swings up and escapes toward the top of the canopy.

Observing later from a high perch, Satka sees her intended meal, now immobile. She carefully climbs to the top of a tree, and begins her feast.

That’s how Satka sees it. But her meal is a shankbone hoisted by a pulley. The tree consists of artfully arranged dead branches. And Satka is not in an Asian forest, but the San Diego Zoo.

This naturalistic setting dramatically contrasts with the barren floor exhibits zoos used many decades ago. It’s better for the animals. When environment resembles what their senses, muscles and brains are adapted for, the animals act much more like their kin in the wild. Abnormal, destructive behaviors decline.

Captivity — zoos use the term “managed care” — is still unnatural for wild animals. Their ancestors never had to depend on people. And the larger animals especially are used to traveling great distances. That’s true even at the San Diego Zoo Safari Park, which at 1,800 acres is one of the largest in the country.

However, within those limits, the San Diego Zoo and zoos around the world continually strive to ease that burden and benefit the species. Zookeepers study field research on the animals in nature, searching for things to incorporate into their program. This may include reproduction -- of great importance for the future of animals whose species is threatened with extinction.

Behavior-based enrichment, as it’s called, stimulates animals with things that pique their interest and challenge them. Animals solve these challenges using their natural behaviors.

San Diego Zoo at forefront of the fine skill of behavioral enrichment, which occupies the animals' attention and recreates natural behaviors.

San Diego Zoo at forefront of the fine skill of behavioral enrichment, which occupies the animals' attention and recreates natural behaviors.

Food isn’t prepared and placed in a bowl, it’s given whole, and may be hidden in the exhibit or placed in an object the animals have to open.

They may be presented with strange smells, rotated to different enclosures — just about anything that makes the animals think, move and use their natural abilities.

“In the wild, a sheep or a deer isn't just going to come lay over in front of the leopard and go, here I am,” said Kelly Murphy, a senior keeper at the zoo. “so they would have to rely on their stalking skills.”

And getting the meat out of a shankbone takes a lot more effort than chewing pre-cut filets.

“You look at the neck and jaw muscles and you can see them really working,” said Murphy, who has cared for leopards for about 10 years.

That same morning, Alba, a 3-year-old Andean bear, occupied herself scooping out seeds from a pomegranate placed at the end of a log, and breaking apart a block of ice placed in her exhibit. Keepers placed these and other items in the exhibit just before Alba emerged from her off-exhibit sleeping area.

“There’s everything from things she has to climb in order to obtain and things she’ll have to break open, said Jessica Sheftel, an animal welfare specialist. “She’ll be using all different muscle groups as well as her mind to obtain those resources.”

Eduardo Contreras / San Diego Union-Tribune

Alba, an Andean bear checks out a pomegranate provided as part of the behavior-based enrichment Program at the San Diego Zoo.

Alba, an Andean bear checks out a pomegranate provided as part of the behavior-based enrichment Program at the San Diego Zoo. (Eduardo Contreras / San Diego Union-Tribune)

This scenario of custom-designed care extends from tigers and bears, primates and the other familiar mammals to reptiles, birds and beyond.

‘We say that every animal needs it and that's all the way down to our insect house,” Murphy said, citing walking sticks as an example. For these insects, different perching areas give them the variety of habitats to exhibit their natural responses.

Enrichment takes place continuously, around the clock. For example, elephants in nature browse at night. So the San Diego Zoo has set up automated feeders. This is in addition to the other enrichment provided to these exceptionally intelligent animals, such as food-filled puzzles and mud ponds for wallowing.

“But you have to remember that it's a lot easier to have an enriched experience for a walking stick than for an elephant,” Murphy said. The walking stick is in a contained environment that you can manipulate. You can completely change that animal's environment on a daily basis.”

Zookeepers customize these stimuli and challenges not only to the species, but to the animal, said Rachel Salant, collection manager for ambassador animals at the Woodland Park Zoo in Seattle. This includes not only our fellow mammals, but birds and even reptiles.

“I think all animals are much smarter than we give them credit for,” Salant said.

“It’s really easy for us to just give their animals given food and walk away,” she said. “But it’s actually been shown that if an animal is presented with food completely free with no obstacles, versus that exact same food presented in a way that requires some sort of problem-solving behavior to get at it, they will choose the harder option to use their brains.”

This concept, called “contrafreeloading,” has also been observed in that peculiar monkey with no tail called Homo sapiens. People value things they have to work for more highly than things they don’t earn.

World leader

The San Diego Zoo has been among the pioneers in behavioral enrichment, said Ed Hansen, CEO of the American Association of Zookeepers in Tucson, Arizona. It began with practical steps such as training primates to present themselves for blood draws and other health procedures. Among other practical uses of training, animals can be coaxed to move from one side of an exhibit to another, so a section can be cleaned.

While food may initially be used as inducement, trained animals will respond just for the mental stimulation, Hansen said.

Over time, zookeepers noticed that the animals appeared eager for training.

“They’ve come to develop relationships with their keepers,” Hansen said. “They expect training sessions will go on in varying parts of the day.”

The San Diego Zoo’s Safari Park has demonstrated feats outsiders might have thought impossible, such as training female rhinos to accept intimate gynecological exams. This training is now taking place with the eventual goal of turning these rhinos into surrogate mothers for a closely related and nearly extinct rhino species.

Positive reinforcement also prevents stress caused by asking animals to do something they don’t want to do, Hansen said. The concept of behavioral enrichment eventually emerged out of these observations.

“The light bulb went off about 30 years ago in the business,” he said. “It’s low stress on the keepers, low stress on the animals and mentally stimulating for the animals under their care.”

But the field keeps moving ahead, as keepers learn more about the vast repertoire of behaviors their charges can exhibit.

“If you're not continually introducing new behaviors, and you're not continually introducing new training techniques, then the animals themselves will cease to be enriched in their captive environment,” Hansen said.

Eduardo Contreras / San Diego Union-Tribune

Senior keeper Hali O'Connor (left) and animal welfare specialist Jessica Sheftel set up a block of ice for Alba the Andean bear.

Satka, the Amur leopard, may soon get the most rewarding and challenging of all enrichments. When she recently showed signs of estrus, or heat, Satka was introduced to another of her species, Oskar. They mated. As of early February, Satka may be experiencing her first pregnancy.

The zoo doesn’t know yet, said Murphy, her keeper, because Amurs show few visible signs of pregnancy.

Behavior is a big clue.

“We’re monitoring her for signs of needing to isolate herself, which is what a pregnant female would do,” Murphy said. “She would seek out a den in a quiet place to have cubs.”

If Satka does exhibit those behaviors, the keepers will set up a den area.

“We will give her a choice of whether she wants to be on exhibit where people can see her or in a back area,” Murphy said.

A successful pregnancy will mean a lot, not just to Satka, but to the welfare of her entire species. Amur leopards are critically endangered. If she has a cub, it will be eventually transferred to another zoo to be a mate.

The San Diego Zoo, along with all zoos accredited by the Association of Zoos & Aquariums, cooperate in breeding programs. These are based on scientific data from a Species Survival Plan. Animals are matched for the best genetic makeup, to increase genetic diversity and create stable populations for future survival of the species.

Alba, the Andean bear, is also part of the program. These bears, the only bears native to South America, are listed as a vulnerable species by the International Union for the Conservation of Nature. She’s housed adjacent to her potential mate, Turbo.

Alba and Turbo know of each other’s existence; they’re allowed to see each other, but not be in the same area at the same time. And when their exhibits are rotated, they can smell the presence of the other — which also qualifies as behavioral enrichment.